Exit code of TortoiseGitMerge should be based on success of a merge resolution
TortoiseGitMerge always returns exit code 0 regardless of the success of a merge resolution.
mergetool.<tool>.trustExitCode can't be used https://git-scm.com/docs/git-mergetool
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information